Marketing-Tap Durability Test
Pause acquisition spend to reveal whether customers compound without it
- Difficulty
- Moderate
- Time to result
- ~months to results
- Steps
- 6
- Confidence
- 98%
During Moonpig's difficult early years, Jenkins tracked how acquired customers bought again and how card recipients discovered the brand. He says each customer attracted roughly a third of another customer through the product itself. The clearest test came when Moonpig spent nothing on marketing for a year and sales still grew by 30 percent. Jenkins now treats the question of what happens when the marketing tap is turned off as an indicator of business quality. The mechanism is to establish cohort, repeat, and referral baselines; reduce paid acquisition under controlled conditions; and observe whether sales collapse, hold, or continue to grow. Continued growth suggests the company is adding enduring customer layers rather than repeatedly renting the same revenue.
Origin
Jenkins says Moonpig survived five difficult years partly because its metrics showed repeat purchases and recipient-driven referrals. In a year with no marketing spend, he says sales grew by 30 percent.
Core principles
- 01Paid growth can hide weak retention
- 02Repeat purchases and referrals create compounding customer layers
- 03Growth without acquisition spend is strong evidence of product quality
- 04A durable business should understand the metrics behind its organic growth
How to run it
- 1
Map the growth sources
Separate paid acquisition, repeat customers, referrals, direct traffic, and product-led discovery in the current sales base.
Pro tip Use cohorts so returning behaviour is not confused with newly purchased traffic.
- 2
Quantify organic contribution
Measure how often customers return and how many additional customers the product or referral behaviour produces.
Pro tip Jenkins tracked recipient exposure because every delivered card displayed Moonpig's name.
Watch out Attribution is imperfect; avoid claiming precision the data cannot support.
- 3
Choose a controlled pause
Reduce or stop a defined portion of acquisition spend for a period long enough to observe the relevant purchasing cycle.
Pro tip Preserve a comparison group or historical baseline where possible.
Watch out Account for seasonality and delayed campaign effects.
- 4
Observe the response
Track sales, active customers, repeat rate, referral rate, margin, and cohort behaviour while paid input is lower.
Pro tip Look for whether earlier customer layers continue producing demand.
- 5
Diagnose the mechanism
If growth persists, verify whether retention, word of mouth, or another organic source explains it; if it collapses, identify the dependency honestly.
Pro tip A test result is more useful when the causal route is understood.
Watch out Do not label all non-paid traffic as durable without examining its source.
- 6
Set the next investment level
Use the result to decide how much paid growth the business can responsibly add without masking product or retention weaknesses.
Pro tip Strengthen the organic mechanism before accelerating a fragile paid engine.
In the wild
Jenkins says Moonpig spent no money on marketing or customer acquisition for one year while sales grew by 30 percent. He attributed the durability to repeat purchasing and the viral effect of recipients seeing and enjoying cards sent by existing customers.
→ The result reinforced his belief that the product and customer base could compound while the company survived its early funding pressure.
Common mistakes
Calling paid revenue durable
Revenue that falls to zero with the marketing tap may still be viable, but it does not demonstrate the compounding quality Jenkins describes.
Ignoring the buying cycle
A pause that is shorter than the repeat or referral cycle can misread a delayed effect as no effect.
Confusing persistence with proof of cause
Continued sales must still be traced to repeat, referral, seasonality, or another mechanism before drawing a strong conclusion.
Is it for you?
Best for
It is best for businesses with repeat purchases, referrals, or product-led discovery and enough runway to run a controlled pause.
Not ideal for
It is not ideal for models that are intentionally one-off, too seasonal for a clean comparison, or unable to pause acquisition without creating disproportionate harm.
From the transcript
“for every customer that we had they'd attract a third of a customer”
“we spent no money on marketing whatsoever”
“what's going to happen when you turn that tap off”
From the episode
Moonpig Founder: How I Built A $150 Million Business WITHOUT Sacrifice: Nick Jenkins